JPH02293522A - Burner fuel supplying device - Google Patents

Abstract

PURPOSE:To cause a leakage of fuel to be impossible and improve a safety factor by a method wherein a flame detecting means detects a flame and a control means is provided for closing a control valve until a pressure valve may detect a fuel pressure within a fuel pipe and opening the control valve as an output signal of the flame detecting means is decreased below a predetermined value. CONSTITUTION:An electrical power control panel 70 prohibits the energizing of a solenoid coil 61 of a solenoid valve 60 as long as two input states may not be generated simultaneously and further includes an electronic circuit responding to a control of the solenoid valve. The first one of these input conditions displays that flames for a burner 30 from a flame sensor 93 and a flame signal transducer 90 are kept. The second condition is made such that a switch 43 for displaying a presence of pressure within a pressure chamber 42 of a pressure switch 41 is closed. In case that these two conditions are not applied simultaneously, the electrical power control panel 70 does not bias the solenoid coil 61, the control valve 62 is kept closed and then a burner system is spaced apart from the main fuel supplying source.

Description

DETAILED DESCRIPTION OF THE INVENTION r Industrial Application Field 1 The present invention relates generally to a fuel supply system, and particularly to a safety device used in connection therewith.

rPrior Art 1 Over the years, several devices have been developed for supplying fuel gas to burners and producing flames for use in various applications. Some common fuel-burning devices are used for cooking, quenching, space heating, and various industrial and commercial applications. The construction of such equipment varies considerably depending on its application, but it generally comprises one or more burner combinations connected to a shut-off valve by a gas pipe; The shutoff valve has an input pipe connected to a main fuel source, such as a commercial gas line. Additionally, many devices are equipped with an electric arc igniter to start combustion. In other systems, the pilot burner contains a small flame that initiates combustion of the fuel in the burner assembly. As such devices have been developed, those skilled in the art have recognized several inherent dangers and safety hazards associated with the use of such flammable gaseous fuels. Various safety devices have been implemented in the past to deal with such potential safety problems. A conventional example of this type will be explained as follows, with reference to FIGS. 1 and 1a. FIG. 1 shows in block diagram form a typical prior art fuel supply system for a burner in which a main gas supply 10 is connected to a fuel supply pipe 11. A solenoid valve 23 includes a main valve 12 connected to the supply pipe 11 and a solenoid 25. The output side of the main valve 12 is connected to an appliance plug 14 by a supply pipe 13. The appliance plug 14 is connected to the burner 15 by a supply pipe 26. A power source 22 connected to a power source such as a public utility line in the prior art is connected to the output side 19.
and a pair of outputs 24. Gas sensor 18 includes prior art circuitry for detecting the presence of unburned fuel gas and emitting an electrical signal indicative of the presence of such gas. Output side or conductor 24
is connected to solenoid 25. Under normal operating conditions, the main valve 12 is opened and fuel gas flows from the main gas supply source 10 through the supply pipe 11, the main valve 12 and the supply pipe 13 to the appliance tap 14. When it is desired to use the burner 15, the appliance tap 14 is opened and fuel gas flows through the appliance tap 14, the supply pipe 26, and into the burner 15. Upon opening of appliance spigot 14, igniter 17 is actuated to ignite the fuel gas flowing from burner 15 and produce one or more flames. During normal operation, the fuel flow described above continues and the flame 16 is connected to burner 1.
It occurs continuously from 5. A solenoid valve 23 includes a main valve 12 connected to the supply pipe 11 and a solenoid 25. The output side of the main valve 12 is connected to an appliance plug 14 by a supply pipe 13. The appliance plug 14 is connected to the gas burner 15 by a supply pipe 26. If fuel gas leaks in the device, the gas sensor 18 responds to the presence of unburned gas and generates a warning signal on the output side, ie, the conductor 19, and the control panel 20, which is connected to the solenoid 25 by the conductor 24, interrupts the power supply. This causes the main valve 12 to close. When the main valve 12 is closed, gas is allowed to flow from the gas supply source 10 through the supply pipe 11. Also shown in FIG. 1a is a circuit diagram of the prior art. When the cock is opened and the cock switch is turned OFF, transistor TR2 stops operating, power transistor TRI is activated, the solenoid valve is forcibly opened, and gas is sent to the burner.

When ignition occurs at the same time, the flame sensor sends a flame signal 3 to the combustion sensing circuit, so that the combustion sensing circuit senses combustion and the operating power of the transistor TR5 is cut off, causing the transistor TR5 to stop operating. When the transistor TR5 stops operating, the transistor TR6 becomes active and the transistor τR3 remains inactive, so that the transistor ゜-. TR1 continues to operate and the solenoid valve remains open. If ignition is not possible, transistor TR6 remains inactive in order to continue operating transistor TR5. As a result, the capacitor C-5 starts to store electricity, and when the voltage of the capacitor C-5 reaches the rated voltage of the Zener diode ZD-1, an overflow current from the capacitor C-5 passes through the Zener diode ZD-1 to the base of the transistor TR3. This causes the transistor TR3 to operate, cutting off the operating current of the power transistor TRI, closing the solenoid valve, and cutting off the gas flow to the burner. Problem to be solved by the invention 1 However, all of the conventional devices described above operate on the assumption that a gas leak has occurred, and there is a risk that the leak may continue even after operation. In the example shown in Fig. 1, since the gas that has leaked out is detected, there are various problems such as the reliability of the gas sensor itself and the influence of the installation position on the detection ability. In addition, in the example of Fig. 1a, if the flame signal line is cut, the current flowing from the resistor R3 to the base of the power transistor TRI will remain as it is, so if the cock is opened and the cock switch is turned OFF, the transistor R9 will be turned off.
operates and transistor TR2 stops operating, so
Power transistor TR1 causes the solenoid valve to remain open regardless of whether there is a flame in the burner or not, so that gas continues to leak. Therefore, the conventional technology has the disadvantage that it cannot completely prevent intentional wetting of gas and inadvertent leakage. rProblem to be Solved by the Invention 1 Therefore, the present invention has been made in view of the above, and provides an improved fuel supply device for a burner that further increases the safety factor to make leakage in the fuel passage impossible. That's true. r l'J5! Means for Solving the Li Points 1 In accordance with the above-mentioned object, the structure of the present invention as summarized in the above-mentioned claims solves the above-mentioned problems by providing a fuel supply system for supplying fuel to the burner from the main source. In the supply device, a fuel pipe connecting the burner to the main supply source, a device stopper with a downstream switch interposed between the burner and the main supply source, and an upstream control valve between the device stopper and the control valve. a pressure valve having a pressure chamber interposed therein and connected to the fuel pipe and a switch responsive to pressure in the fuel pipe;
ignition means for igniting fuel exiting the burner; flame sensing means/means for detecting the presence of a flame in the burner and producing an output signal indicating the combustion characteristics of the flame in the burner; an appliance stopper, a control valve, an ignition means, and a flame. coupled to a sensing means;
The flame sensing means senses a flame and causes the control valve to remain closed until the pressure valve detects the fuel pressure in the fuel pipe, and when the output signal of the flame sensing means falls below a predetermined magnitude, the control valve is closed. This technical measure is characterized in that it is equipped with a closing control means. Embodiment 1 Next, an embodiment of the present invention will be explained along with its operation. FIG. 2 shows in block diagram form the fuel supply system of the present invention in which a burner 30 is connected to a pipe 32 which is connected to an appliance tap 33. Appliance tap 33 with switch 34 is connected by pipe 35 to a control valve 62 which in turn is connected by pipe 63 to a main fuel source (not shown). The control valve 62 also forms the valve portion of a solenoid valve 60 which includes a pressure switch 41 having a solenoid coil 61 operatively connected to the control valve 62 in accordance with prior art solenoid valve manufacturing techniques. is pipe 4
The pressure chamber 42 is connected to the pipe 35 by a mounting seat 53 and a diaphragm 51, and has a volume sufficient to hold a sufficient amount of fuel gas to ignite the burner 30. The diaphragm 51 is in the uppermost position against the spring 45 when the fuel gas is sealed in the pressure chamber 42 at a predetermined pressure, and a magnet 44 that opens and closes the switch 43 is set in the diaphragm 51. The spring 45 is attached to the top of the bead 50 and the diaphragm 5
The switch 43 is housed in the upper part of the magnet 1 and applies a downward force to the diaphragm 51, and the switch 43 is turned on and off in response to the contact and separation of the magnet 44 due to fluctuations in gas pressure within the pressure chamber 42'. When the appliance plug 33 is opened and the switch 34.6 is turned OFF, the igniter 100 is activated and the conductor 36 is connected to the electrode 38.6.
The flame signal transducer 90 senses combustion and the solenoid valve 60 is temporarily opened from the power control panel 70 via the conductor 80. The gas pressure in the pressure chamber 42 decreases, the magnet 44 goes down, the switch 43 turns OFF, and a signal indicating that the gas pressure has decreased is sent from the conductor 54 to the power control panel F0, which cancels the signal that causes the solenoid valve 60 to open. A delay circuit is provided in the control panel 70 to ignore the output from the switch 43 for a predetermined period of time. The power control board 70 is provided with a power input lead 84 connected to a prior art AC power source by a power control circuit and a plug 85 operative as described below, and the power control board 70 also includes a solenoid coil of the solenoid valve 60. 61.Conductor wires 80, 81, 82, and 83 are connected to the end of the output terminal connected to the emergency power source 27 and the output signal receiver 28, and the power input conductor 84 of the power control panel includes prior art circuitry that generates electrical power in response to a power interruption. An output signal receiver 28 is connected to the power control board 70 and is operative to receive auxiliary purpose input signals and provide an output signal on conductor 81 to remotely control the functions of the power control board 70. Further, a conductor 54 connects the power control panel F0 to the switch 43 of the pressure switch 41. Ignition system ioo includes prior art electronic circuitry that produces a high voltage ignition output. Ignition device 100 includes a pair of conductive wires 74
- Connected to the power control panel 70 by 75. A pair of electrodes 38 and 39 are housed within the insulator 3 and connected to the ignition device 100 by a high voltage conductor 36. A switch 34 is operatively connected to the appliance spigot 33 and electrically connected to a power control board 70 by a pair of conductors 72 and 73. A flame signal transducer 90 is connected to the power control panel f0 by a conductor 71, a flame sensor 93 is supported by a sensor holder 92, and a flame signal transducer 90 is connected to the power control panel f0 by a conductor 71.
・Connected to the juicer 90. In operation, under normal conditions, before igniting the flame of burner 30, the apparatus shown in FIG. 2 is in a stopped state with appliance tap 33 closed and switch 34 turned on. Additionally, the pressure switch 41 is pressurized by gas in a pipe 35 positioned between the closed appliance tap 33 and the closed control valve 62 of the solenoid valve 60. Pressure switch 4! When pressurized, the diaphragm 51 is pushed upward, compressing the spring 45 and moving the magnet 44 towards the switch 4.
Position it close to 3. When positioned in close proximity to switch 43, magnet 44 causes switch 43 to close and sends a signal via conductor 54 to power control board 70 that the fuel supply line is pressurized. When there is no flame in the burner 30 by closing the appliance spigot 33, the flame sensor 93 detects the absence of a combustion flame, and in response, the flame signal transgenerator 90 is connected to the power control board F0 by conductor F1. A signal is generated representing a signal indicating an induced flameless condition. Therefore, in the initial state of the apparatus shown in FIG. 2 before a flame is generated in the burner 30, there is a certain amount (sufficient to ignite the burner 30) in the pipe 35 of the pressure switch 41 and the pressure chamber 42. amount) of pressurized fuel is held. At this point, the device is stopped and no fuel gas flows to the burner 30. To start the operation of the device shown in FIG. 2, open the appliance plug 33 and turn off the switch 34. The current flowing to the power control panel 70 via the conductor 72 and the pipe 3 is cut off. An activation signal is transmitted to the ignition device 100 through a conductor 74 and a fuse 5. The igniter 100 is activated and the electrode 3
B. At the same time that discharge occurs between 39 and ignition is started, the pressure chamber 42 and pipe 35 are opened by opening the appliance plug 33.
The fuel gas stored inside flows out from the burner 30 and a flame 31 is lit. During the initial fuel flow phase, solenoid valve 60 remains closed and the only fuel supplied to burner 30 is the pressurized fuel in chamber 42 and pipe 35. Once burner 30 is ignited and flame 31 is produced, flame sensor 93 provides an input via conductor 91 to flame signal transducer 93 indicating that flame 31 is present. Flame signal transducer 90 converts the output of flame sensor 93 into an electrical signal indicating that the burner has ignited at no time and is applied via conductor F1 to power control panel F0. Under the above-mentioned situation, when the flame display signal is present on the conductor 71 at the same time as the appliance tap 33 is opened, the solenoid coil 61 of the solenoid valve 60 is sent to the power control panel 70 via the conductor 80.
generates an output signal to open the control valve 62 and allow fuel gas to flow from the main gas supply source through the pipes 63 and 65 to replenish the fuel being burned in the burner 30. Furthermore, a portion of the gas flowing from the main source is allowed to flow into pressure chamber 42 to replenish the pressure within pressure chamber 42 and switch 43 remains closed. To extinguish the flame 31 of the burner 30 in connection with normal shutoff, the appliance tap 33 is closed and the switch 34 is turned ON. Then, the flow of fuel gas to the burner 30 is interrupted and the flame 31 is extinguished. When flame 31 is extinguished, flame sensor 9
3 indicates that there is no flame 31 to the flame signal transducer 90 via a conductor 91, and this flame signal transducer 90 changes the signal related to the power control panel f0 via a conductor 71. If a flameless condition exists, power control 1170 interrupts power supply to solenoid coil 61 of solenoid valve 60, thereby closing control valve 62. When the control valve 62 is closed, a quantity of fuel under pressure is admitted into the pipe 35 of the pressure switch 41 and the pressure chamber 42. At this point, the ignition system is shutting off normally and has returned to the original state described above. Having considered the normal operation and functioning of the device of the present invention, the various disturbances to which the device is responsive will now be described. When a pressure leak occurs in the device, the pressurized fuel gas contained in the pipe 38 of the pressure switch 41 and the pressure chamber 42 escapes, reducing the pressure in the pressure chamber 42. Pressure chamber 4
When the pressure inside 2 decreases, at a certain pressure point the diaphragm 5
The force of the spring 45 applied to the magnet 44 pushes the magnet 44 downward. When the magnet 44 is pushed downward, the switch 43 is turned OFF and communicated with the power control panel 70 through the conductor 54.
The power control panel 70 detects the condition during the switch 43 due to pressure leakage and prevents the solenoid valve from opening until the pressure is restored. Therefore, when switch 34 is in the ON state, any attempt to open valve 6o will fail and the system will be isolated from the mains supply by closed control valve 62. Therefore, the amount of gas that can escape from the device is only a small amount that is contained within pressure chamber 42 and pipe 35 and can be calculated using the equation shown in FIG. In the equation shown in FIG. 3, Q represents the leakage amount, q゜ represents the capacity of the pressure chamber, P represents atmospheric pressure, P゜ represents the pressure of the fuel gas, and D represents the diameter of the pipe 35. , and L indicates the length of the pipe 35. This amount does not normally pose a significant safety hazard and the equipment is therefore protected against fuel leaks. If the flame 31 of the burner 3o is extinguished by sudden intake of air while the device is in operation, the flame sensor 93 detects the absence of a flame and sends a flame signal via the conductor 91. transmitted to transducer 90. Next, the flame signal transistor 90 is connected to the power control panel 70 by the conductor 71.
This output signal causes the power control board 70 to interrupt the closed state of the control valve 62 of the solenoid valve 60 by cutting off the transmission of power to the solenoid coil 61. Therefore, when flame 31 is extinguished, control valve 62 is closed and the system is again isolated from the main fuel supply.

According to one important aspect of the invention, power control board 70 includes two
It includes electronic circuitry adapted to respond to control of the solenoid valve by inhibiting energization of the solenoid coil 61 of the solenoid valve 60 unless two input conditions occur simultaneously. The first of these input conditions is the input from the burner 30 from the flame sensor 93 and the flame signal transducer 90.
It is an indication that the flame is preserved. The second condition is that the switch 43, which indicates that pressure is present in the pressure chamber 42 of the pressure switch 41, is closed.
If these two conditions do not exist at the same time, the power control panel 7
0 does not energize the solenoid coil 61 of the solenoid valve 60 and the control valve 62 remains closed, isolating the burner system from the main fuel supply. In FIG. , in this curve, the vertical axis 10
1 indicates the flame sensor current and the vertical axis 102 indicates time.
Axes 101 and 102 intersect at origin 103. Axis 101 has several milestones including a critical point 114, a minimum normal current point 105, and a maximum current point 104. Origin 1
03, and when the flame generation of the device of the present invention, i.e., burner ignition, starts, the point 1 indicates the completion of burner ignition.
11 is the slope portion 110 of the curve 100. Thereafter, as time passes, the burner functions within its normal operating range and the flame sensor receives current between points 104 and 105. At a certain point on curve 100, indicated by arrow 115 and point 112, the oxygen in the room decreases due to continued combustion by flame 31 of burner 30. From origin 103 to point 1
The distance shown by the arrows up to 12 is variable as a function of the volume of the chamber in which the burner 30 is acting. As depletion begins, the output current of flame sensor 93 decreases commensurately, eventually using the oxygen in the room to the point where it becomes dangerously depleted if burner 30 remains activated.
According to the present invention, the control panel F0 operates in response to currents below the minimum normal current to detect impending oxygen depletion and prevent the oxygen in the room from decreasing to a dangerous point. Prior art detection devices to prevent oxygen depletion rely on changes in flame characteristics due to a decrease in the amount of oxygen available.
Many devices use changes in flame height relative to the burner as the primary detection characteristic of impending oxygen depletion. Such flame height detection devices are somewhat more complex and less reliable than the detection device of the present invention. In contrast, the device of the present invention uses the current generated by the flame sensor to generate a signal indicating the burner's combustion status. In particular, referring to FIGS. 3 and 4 at the same time, when the flame sensor 93 detects the flame 31 of the burner 30, the conductor 91
A current is generated at , which current is directly related to the flame current processed by flame signal transducer 90 and applied by flame 31 to flame sensor 93, as previously discussed. Therefore,
Unlike prior art devices that detect secondary effects of oxygen depletion such as flame height, the present invention utilizes electrical signals that have a direct and reliable relationship to flame conditions. Next, referring to FIG. 4, the normal operation area is marked 10.
It should be noted that this corresponds to the range of sensor current shown in 4.105. Similarly, the emergency or depletion level of the combustion curve also corresponds to the lower flame sensor current at level 114. Briefly, the present invention directly monitors the emergency output flame status of a burner system through its unique current sensing method. Therefore, as can be seen in FIG. 4, the reduced oxygen source condition de-energizes the flame, thus producing a reduced flame sensor current. The present invention uses this reduced current to close the main supply valve and issue an audible warning. The one shown utilizes a pressure switch as a reservoir with a predetermined volume of fuel gas to initiate ignition of the burner system, and the pressure switch and flame sensor cooperate to connect the burner system connection to the main fuel supply line. This is a fuel supply device for a burner that indicates the existence of an appropriate condition for opening the burner. The device also uses electrical signals to monitor burner fuel status and indicate flame status to detect oxygen depletion.

From the above description, those skilled in the art will recognize that a variety of structures can be used to construct the power control panel 70. In a preferred form, the power control board 70 includes a plurality of signal processing channels that cooperate with each other to detect the simultaneous occurrence of the conditions described above and to activate or deactivate the solenoid valve 60 as appropriate. Although specific embodiments of the invention have been shown and described, those skilled in the art will recognize that various changes and modifications may be made without departing from the broader aspects of the invention. Accordingly, the scope of the claims is intended to include all such modifications and variations. Effects of the Invention 1 Since the present invention is as described above, it is assumed that there is a flame in the burner before the control valve opens, so if there is a leak downstream of the control valve, the burner will not ignite. Conversely, it is possible to provide a fuel supply device for a burner that guarantees safety by burning the outflowing fuel whenever the control valve is opened. Furthermore, since the present invention detects oxygen deficiency at the flame, accidents caused by oxygen consumption during combustion can be prevented more reliably and at a lower cost than other methods. Furthermore, it is worth noting that the control valve is configured not to open unless the above-mentioned conditions are met, so there is no possibility of intentionally causing a leak, and even if some kind of failure occurs, the control valve will not open. , it is possible to provide an extremely reliable burner fuel supply system that fails when the control valve fails to open.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a typical prior art fuel supply system, FIG. 2 is a typical ivy diagram of the burner fuel supply system of the present invention, and FIG. 3 is a diagram showing the maximum amount of fuel gas lost by the system of the present invention. Figure 4 is an oxygen depletion chart for gas burners. 10... Main supply source, 30... Burner 31...
flame, 61... if control valve 70... control means;
90...Flame detection means 1. Case description 1999 Patent Application No. 1 1 5453 2. Name of the invention Burner fuel supply device 3. Relationship with the case of the person making the amendment

Claims (5)

[Claims] (1) A burner fuel supply device that supplies fuel from a main supply source to a burner, which has a fuel pipe that connects the burner to the main supply source, and a downstream switch interposed between the burner and the main supply source. a pressure chamber interposed between the appliance tap and the upstream control valve and connected to the fuel pipe and a pressure valve having a switch responsive to pressure in the fuel pipe; and fuel exiting the burner. an ignition means for igniting the burner; a flame sensing means for sensing the presence of a flame in the burner and producing an output signal indicative of combustion characteristics of the burner flame; ,
The flame sensing means senses a flame and causes the control valve to remain closed until the pressure valve detects the fuel pressure in the fuel pipe, and when the output signal of the flame sensing means falls below a predetermined magnitude, the control valve is closed. A burner fuel supply device comprising: closing control means. (2) The burner fuel supply of claim 1, wherein the pressure chamber includes a movable diaphragm, the volume of the pressure chamber increases to accommodate fuel under pressure, and contains sufficient fuel to ignite the burner. Device. (3) The burner fuel supply system according to claim 1, wherein the control means operates to close the control valve when the pressure valve detects fuel loss. (4) The burner fuel supply system of claim 1, wherein the control means operates to close the control valve when the flame sensing means detects that there is no flame in the burner. (5) the flame sensing means is adapted to generate an output current related to the flame of the burner, and the control means connected to the flame sensing means determines that the output current of the flame sensing means is at an oxygen depletion level less than or equal to the output current value; 2. The burner fuel supply system of claim 1 operative to close the control valve when the fuel decreases to .